Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (529 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Drugs that block negative regulator immune checkpoint proteins (e.g., pd-1 receptor and ctla-4 antigen) thereby increasing suppressed immune activation in immunotherapies.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Checkpoint Inhibitors, Immune; Immune Checkpoint Blockers; Checkpoint Blockers, Immune; Immune Checkpoint Inhibitor; Checkpoint Inhibitor, Immune; CTLA-4 Inhibitors; CTLA 4 Inhibitors; Cytotoxic T-Lymphocyte-Associated Protein 4 Inhibitors.
Where it fits in the MeSH classification
- Broader topics
- Molecular Mechanisms of Pharmacological Action; Antineoplastic Agents, Immunological
Related concepts
- Immune Checkpoint
- Pd-1 Receptor
- Ctla-4 Antigen
Research landscape
PubMed indexes 21,474 records tagged with the MeSH heading “Immune Checkpoint Inhibitors” (counts retrieved 2026-10-29). 21,463 of them (99.9%) were published from 2020 onward, and the busiest period so far is 2020 onward with 21,463 records.
Reviews account for 7,017 records (32.7%) and meta-analyses for 1,232. Randomized controlled trials number 218 (1.0%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 0 |
| 2000-2009 | 0 |
| 2010-2019 | 148 |
| 2020 onward | 21,463 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 7,017 | 32.7% |
| Meta-analyses | 1,232 | 5.7% |
| Randomized controlled trials | 218 | 1.0% |
Method: PubMed query "Immune Checkpoint Inhibitors"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in pharmacology
Drug evidence builds in layers: laboratory pharmacology describes how a compound acts, pharmacokinetic studies describe how the body handles it, and randomized trials test whether it helps and what harms it causes. Post-marketing surveillance and observational studies reveal rarer adverse effects but cannot prove causation. This page is educational and is not a recommendation to start, stop or change any medicine; decisions about treatment belong with a qualified clinician.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Anti-PD-1 plus anti-CTLA-4 blockade overcomes immune exclusion in NSCLC brain metastases by enhancing CD8+ T cell responses and promoting tertiary lymphoid structure formation | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42414284 · DOI · PMC13342341 |
| Radiotherapy and immunotherapy in cancer treatment: mechanisms of clinical synergy | 2026 | Review article Design not recorded in structured metadata | 1 | cc by PMID 42606129 · DOI · PMC13476145 |
| Emerging Immune-Based Therapeutic Strategies in Hepatocellular Carcinoma | 2026 | Review article Design not recorded in structured metadata | 1 | cc by PMID 42387819 · DOI · PMC13323950 |
Anti-PD-1 plus anti-CTLA-4 blockade overcomes immune exclusion in NSCLC brain metastases by enhancing CD8+ T cell responses and promoting tertiary lymphoid structure formation [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Brain metastases (BrMs) in non-small cell lung cancer (NSCLC) respond poorly to anti-PD-1 monotherapy, but the underlying immune resistance remains incompletely defined.
- Closing excerpt
- These findings manifest increased adaptive immune response of dual checkpoint blockade in NSCLC BrMs.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (154 words)
Brain metastases (BrMs) in non-small cell lung cancer (NSCLC) respond poorly to anti-PD-1 monotherapy, but the underlying immune resistance remains incompletely defined. Here we integrate clinical outcome analyses, paired human tissue profiling and syngeneic mouse models to characterize the BrM immune microenvironment. Clinical analyses suggest improved intracranial disease control with nivolumab plus ipilimumab compared with nivolumab alone. Paired human specimens show that BrMs contain fewer cytotoxic T lymphocytes (CTLs) and tertiary lymphoid structures (TLSs) than primary tumors, defining an immune-excluded phenotype. A syngeneic BrM model recapitulates this phenotype and resists anti-PD-1 monotherapy, whereas combined anti-PD-1 and anti-CTLA-4 blockade suppresses tumor growth and prolongs survival. Single-cell RNA sequencing, flow cytometry and immunofluorescence show increased CTL infiltration and effector function after combination therapy. CD8+ T cell depletion abrogates therapeutic benefit, and combination therapy expands T follicular helper-like cells and induces TLS-like structures. These findings manifest increased adaptive immune response of dual checkpoint blockade in NSCLC BrMs.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42414284 · DOI · PMC13342341
Radiotherapy and immunotherapy in cancer treatment: mechanisms of clinical synergy [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Synergizing radiotherapy (RT) with immune checkpoint inhibitors has emerged as a promising strategy for solid tumors.
- Closing excerpt
- Furthermore, we explore how AI-driven analysis of radiomics and multiomics data is being applied to predict responders and personalize treatment planning.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (163 words)
Synergizing radiotherapy (RT) with immune checkpoint inhibitors has emerged as a promising strategy for solid tumors. RT acts as a potent immunomodulator, capable of functioning as an in situ vaccine through the induction of immunogenic cell death and activation of innate immune sensing, thereby promoting DC maturation and CD8+ T cell responses. However, RT also triggers counter-regulatory immunosuppression, including PD-L1 upregulation and the recruitment of suppressive cells, providing the biological rationale for synergy. Here, we systematically review advances in radioimmunotherapy, covering immunomodulatory mechanisms, clinical optimization of dose and sequencing, and the emerging role of artificial intelligence (AI) in guiding treatment paradigms. We adopt a spatial interaction-centric perspective to synthesize current knowledge on how RT governs the DC/CD8+ T cell interaction axis across the tumor microenvironment and tumor-draining lymph nodes, aiming to chart a rational course from empirical combination toward personalized, precision radioimmunotherapy. Furthermore, we explore how AI-driven analysis of radiomics and multiomics data is being applied to predict responders and personalize treatment planning.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42606129 · DOI · PMC13476145
Emerging Immune-Based Therapeutic Strategies in Hepatocellular Carcinoma [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality worldwide despite recent advances in systemic therapy.
- Closing excerpt
- Together, these insights emphasize the need for biomarker-guided patient stratification and integrated therapeutic strategies to improve the clinical efficacy of immunotherapy in HCC.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (212 words)
Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality worldwide despite recent advances in systemic therapy. The introduction of immune checkpoint inhibitors has substantially expanded treatment options for advanced disease; however, durable responses are observed only in a subset of patients. Increasing evidence indicates that this limited efficacy is largely driven by the complex immune landscape of HCC, which is shaped by disease aetiology, tumour microenvironment-mediated immune suppression, and impaired innate immune surveillance. Chronic viral hepatitis and metabolically driven liver diseases represent the principal drivers of HCC and profoundly influence immune regulation within the liver. Persistent antigen exposure, metabolic reprogramming, and stromal remodelling contribute to dysfunctional T- and natural killer (NK) cell responses, while immunosuppressive components of the tumour microenvironment, including tumour-associated macrophages, myeloid-derived suppressor cells, regulatory T cells, and inhibitory ligands such as HLA-G, facilitate immune escape and therapeutic resistance. In this review, we discuss recent advances in HCC immunotherapy, focusing on emerging checkpoint pathways such as TIGIT and Tim-3, glypican-3 targeted cellular therapies and bispecific antibodies, and NK cell-based therapeutic strategies. We further highlight the role of liquid biopsy approaches for treatment monitoring and biomarker development. Together, these insights emphasize the need for biomarker-guided patient stratification and integrated therapeutic strategies to improve the clinical efficacy of immunotherapy in HCC.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42387819 · DOI · PMC13323950
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Sex differences in adverse events among cancer patients receiving immune checkpoint inhibitors: the MOUSEION-07 systematic review and meta-analysis [4]
- Research article Impact of pre-transplant immune checkpoint inhibitor use on post-transplant outcomes in HCC: A systematic review and individual patient data meta-analysis [5]
- Research article Efficacy and safety of immune checkpoint inhibitors for individuals with advanced EGFR-mutated non-small-cell lung cancer who progressed on EGFR tyrosine-kinase inhibitors: a systematic review, meta-analysis, and network meta-analysis [6]
- Research article Neoadjuvant Immune Checkpoint Inhibitors Plus Chemotherapy in Early Breast Cancer: A Systematic Review and Meta-Analysis [7]
- Research article Prognostic value of inflammatory markers NLR, PLR, LMR, dNLR, ANC in melanoma patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review [8]
- Research article Immune-related serious adverse events with immune checkpoint inhibitors: Systematic review and network meta-analysis [9]
References
- Hosoya K, Ozasa H, Tsuji T, Oi M, Shima Y, Suminaga K, et al.. Anti-PD-1 plus anti-CTLA-4 blockade overcomes immune exclusion in NSCLC brain metastases by enhancing CD8+ T cell responses and promoting tertiary lymphoid structure formation. . 2026. PMID 42414284 · DOI · PMC13342341
- Lu L, Deng L. Radiotherapy and immunotherapy in cancer treatment: mechanisms of clinical synergy. . 2026. PMID 42606129 · DOI · PMC13476145
- Kah J, Dammermann W, Lueth S. Emerging Immune-Based Therapeutic Strategies in Hepatocellular Carcinoma. . 2026. PMID 42387819 · DOI · PMC13323950
- Vitale E, Rizzo A, Maistrello L, Guven DC, Massafra R, Mollica V, et al.. Sex differences in adverse events among cancer patients receiving immune checkpoint inhibitors: the MOUSEION-07 systematic review and meta-analysis. Sci Rep. 2024. PMID 39550353 · DOI · PMC11569249
- Rezaee-Zavareh MS, Yeo YH, Wang T, Guo Z, Tabrizian P, Ward SC, et al.. Impact of pre-transplant immune checkpoint inhibitor use on post-transplant outcomes in HCC: A systematic review and individual patient data meta-analysis. J Hepatol. 2025. PMID 38996924 · DOI · PMC11655254
- Zhao Y, He Y, Wang W, Cai Q, Ge F, Chen Z, et al.. Efficacy and safety of immune checkpoint inhibitors for individuals with advanced EGFR-mutated non-small-cell lung cancer who progressed on EGFR tyrosine-kinase inhibitors: a systematic review, meta-analysis, and network meta-analysis. Lancet Oncol. 2024. PMID 39159630 · DOI
- Villacampa G, Navarro V, Matikas A, Ribeiro JM, Schettini F, Tolosa P, et al.. Neoadjuvant Immune Checkpoint Inhibitors Plus Chemotherapy in Early Breast Cancer: A Systematic Review and Meta-Analysis. JAMA Oncol. 2024. PMID 39207778 · DOI · PMC12422158
- Ou Y, Liang S, Gao Q, Shang Y, Liang J, Zhang W, et al.. Prognostic value of inflammatory markers NLR, PLR, LMR, dNLR, ANC in melanoma patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review. Front Immunol. 2024. PMID 39493767 · DOI · PMC11527641
- Oliveira C, Mainoli B, Duarte GS, Machado T, Tinoco RG, Esperança-Martins M, et al.. Immune-related serious adverse events with immune checkpoint inhibitors: Systematic review and network meta-analysis. Eur J Clin Pharmacol. 2024. PMID 38372756 · DOI · PMC11001692
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.